1. Field of Endeavor
The invention relates to a device for performing a measurement on a rotating part of rotating machinery, and a corresponding method, as well as a measurement and sender unit for performing a measurement on a rotating part of rotating machinery.
2. Brief Description of the Related Art
Condition monitoring of rotating machinery, such as steam or gas turbines or generators, is usually carried out during overhauls of the machinery at slow rotating speeds. For monitoring, measurement systems are used, which are connected by cables with an outside processing unit for processing the measuring data. This method is time consuming and also inapplicable for online condition monitoring of the rotating machine. However, for long time reliability of rotating machinery, it may be essential to continuously monitor the condition of the machinery online in order to detect undesired forces which can reduce the lifetime of the machinery.
Continuous monitoring would be important in applications such as the one described in the following. In power plants, several rotating machines may be coupled together in order to form a shaft with a considerable length conveying the forces of the machines. The shaft sections of the machines are aligned and connected by means of shaft couplings. Bearings may be arranged between the couplings and at the end of the shaft for pivoting the shaft. Misalignment of the shaft sections can generate undesired forces which may cause vibrations, shaft bending, a reduced bearing and coupling life, and a reduced efficiency of the power plant.
WO 92/08962 discloses a method and a device for aligning shaft sections at a rotor shaft having several parts. The shaft sections are joined by means of couplings and the shaft is journal led in bearings on each side of the couplings. Strain gauges are fixed to each side of a coupling. Their measuring values indicate the strain at each shaft coupling. The bending moment in the shaft coupling is evaluated by a processing unit and then utilized in a moment minimization unit. Furthermore, a third unit can utilize indications of allowed angular deviations for each coupling in order to minimize the bearing movements which have to be made to minimize the total residual moment in the couplings.
Therefore, there exists a need to provide a device, method, and measurement and sender unit for performing a measurement on a rotating part of rotating machinery, which allow for particularly long term online monitoring.